Attachment plug



Jan. 9, 1951 J. E. FDLOOD 2,537,819

ATTACHMENT PLUG Filed Jan. 12, 1946 NVENTOR r i ll 2 \JQWZZJ FZUOLt ZGMbun ATTORNEYS Patented Jan. 9, 1951 UNITED STATES ATTACHMENT PLUG JamesE. Flood, Norwich, Conn, assignor to The Plastic Wire & CableCorporation, Norwich, Conn, a corporation of Connecticut ApplicationJanuary 12, 1946, Serial No. 640,920

This invention relates to electrical plugs such as are attached toappliance and extension cords to be detachably connected toplug-receptacles.

An object of this invention is to provide an attachment plug which iseconomical to make and assemble with the wire connected contact bladesand yet in which, when assembled, the anchored ends of the blades arepermanently secured in the plug body against removal in any mannerexcept by the destruction of the body of the plug.

Heretofore, in plugs of this type in which spaced blade-receivingpassages pass through the plug and converge and merge with thecord-receiving cavity at the opposite end of the plug it has been thepractice to connect the blades to the conductors, spread the end of theplug hav- 2 Claims. (Cl. 173 361) ing the cord-receiving cavity untilthe cord-receiving cavity is in substantial alignment with theblade-receiving passages and then draw the assembled blades andconductors in from the back of the plug through the passages intoposition with the blades projecting from the front of the plug. This hasbeen an expensive operation and requires a good quality of rubber in theplug body to permit the extension thereof. Many times in the assemblingoperation the end of the insulation on the conductor engages the edge ofthe plug body and is stripped back unless precautions are taken toprotect this end.

The present invention overcomes these diniculties by making the body ofa flexible material which may be rubber, synthetic rubber, syntheticresins, or acetates and providing a slit through the usual solid centralportion between the bladereceiving passages of the body from end to endthereof so that it extends from the cord-receiving cavity to the frontface of the plug. When a squeezing action is applied to the side edgesof the plug the slit opens or spreads and facilitates insertion of theconductor from the rear and the assembly of the body and the conduc torwith its attached contact blades from the front of the plug body afterthe blades have been attached. It will be noted that in this manner anyaction of the plug body on the insulation of the conductor will be topull the insulation into the plug rather than strip it back. After theassembly is completed and the blades are located in the blade-receivingand anchoring passages the surface of the body produced by the slit maybe cemented or otherwise inseparably adhered together to make thecentralportion of the body one solid mass and thereby prevent theanchoring means carried on the contact blades from becoming dislodgedfrom their cooperating ele.v ments in the plug,

In the form of the invention herein illustrated as exemplary thereof,the body is molded with blade-receiving passages in which the blades areconfined and these are in communication With the transverse central slitso that as the wires with the blades attachedare drawn backwardly intothe body, the blades move into the slots while the attached wires passthrough the slit until the cord-receiving cavity in the body is reached.

Other features and advantages of the invention will be apparent from thespecification and claims when considered in connection with the drawingsin which:

Figure 1 shows a sectional view of the plug taken along lines i---! ofFig. 2.

Fig. 2 is a front end view of the plug body.

Fig. 3 is a sectional view similar to Fig. 1 showing the prongs inposition.

Fig. 4 is an end View similar to Fig. 2 showing the blades in place andthe slit closed.

Fig. 5 is a View similar to Fig. 3 showing an-' other form of theinvention.

Fig. 6 is a perspective view showing the blades being withdrawn into theplug body.

As shown in the drawings the plug body ill of flexible material such asrubber, synthetic rubber, polyvinyl chloride and the like syntheticresins or acetates has a conductor-receiving aperture it formed at theback end thereof. Thisopens into a conductor-receiving cavity l2 whichhas a pair of blade-receiving slots or passages [3 extending therefromto the forward end of the plug and on opposite sides of a central core Il. The outer walls i ia of the central core form one wall of each of thepassages 3. The walls i la are preferably provided with means forcooperating with the blades to anchor the blades in the passage. Thismeans is herein illustrated as a notch it formed in the wall andproviding an abutment 50.. As is shown in Fig. 2 the central core isdivided by a slit i6 which extends from side to side thereof andintersects the blade passages.

The conductor li may have any type of insulation it thereon and isprovided with two insulated wires is which are connected to the contactblades 2!! which project from the front face of the plug for insertioninto the usual plug receptacle. The blades are anchored in thebladereceiving passages by tangs 2i lanced therefrom and projectingforwardly so as to engage the abutment H500 when the blades are inanchored position.

In assembling the plug of the present invention, the plug body of Fig. 1is grasped at the sides Ina thereof and compressed so as to compress thematerial of the body and spread open the slit [6 in the central core.The conductor I7 is fed through the aperture I I, the conductorreceivingcavity [2, and through the spread slit as shown in Fig. 6. The bladesare then attached to the wires extending from the insulation bysoldering or any other suitable means. The assembled blades andconductor are then drawn back into the body through the front facethereof with the blades being positioned in the bladereceiving passagesand the wires passing along the slit portion of the central core untilthey move into the conductor-receiving cavity and the tangs engage theabutment la in the anchored position as shown in Fig. 3.

The slit in addition to providing for passage of the wires connected tothe blades as they are moved into the plug also permits the anchoringtangs 2! to readily drop into the notches l5 and interlock therewithwithout tearing or damaging the wall of the passage.

When the blades are in anchoring position, the bent inner ends 29a willrest against the wall of the passageway as shown in Fig. 3 and cooperatewith the tang 2! to hold the blade against movement in either direction.

After the blades have been located in anchored position, the walls ofthe slit are rendered tacky and pressed together so as to permanentlyseal the slit as shown in Fig. 4 and render the core a unitarystructure. This adds rigidity to the wall 14a and anchoring meanscarried thereby so that the blades are securely held in position andcannot be removed without destroying the body of the plug.

The slit may be permanently sealed by coating the walls thereof with asolvent for the body material by injecting or otherwise applying thesolvent thereto. When the walls are pressed together the material mergesand the central core becomes a solid mass. Also, the slit may bepermanently closed by suitable adhesives applied to the walls of theslit to cause them to adhere together and to hold the blades inposition.

If desired, a suitable adhesive may be also applied to the insulation I8before the conductor is withdrawn into the plug to secure it to thewalls of the aperture II. By securely bonding the two surfaces togetherth insulation is prevented from pulling back or stripping in use.

The form of the invention of Fig. 5 is similar to that shown in Fig. 3with the exception that the tangs 21a and notches [5b are in reverseposition to that shown in Fig. 2. This plug is assembled in preciselythe same manner as is the plug of Fig. 3. The slit is particularlyadvantageous in connection with this type of blade since it permits thetang to pass into the notch without tearing or damaging the wall.

Variations and modifications may be made within the scope of thisinvention and portions of the improvements may be used without others.

I claim:

1. An attachment plug having a body of flexible material provided withblade-receiving and anchoring passages therein on each side of a centralcore and a conductor-receiving aperture merging with the inner ends ofsaid passages; and a conductor disposed in the aperture and havingblades provided with anchoring tangs connected thereto and anchored inthe passages in the body, said core having a slit ending in saidpassages and having a recess facing each respective passage, said slithaving walls which may be resiliently urged apart to facilitate thepassage of the conductor and its wires and attached contact blades andanchoring tangs into the body from the front thereof during assemblywhen the body is flexed to cause the slit to open, and said recesscooperating with and being engaged by said anchoring tangs on the bladesto anchor the blades in the passages.

2. The invention as defined in claim 1, wherein adhering means isapplied to the slit to secure the walls thereof together permanently.

JAMES E. FLOOD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,824,657 Coldwell Sept 22, 19311,871,278 Powell Aug. 9, 1932 2,094,046 Short Sept. 28, 1937 2,169,219Brownstein Aug. 15, 1939 2,173,820 Andre Sept. 26, 1939 2,181,575Chirelstein Nov. 28, 1939

